WO2002074523A1

WO2002074523A1 - Plant for production of flexible tubes made from plastic with moulding of the head on top of the skirt carried out by continuously moving tools

Info

Publication number: WO2002074523A1
Application number: PCT/FR2002/000950
Authority: WO
Inventors: Bertrand Gruau; Hervé ZAKRZEWSKI; Michel Bosshardt
Original assignee: Cebal S.A.S.
Priority date: 2001-03-19
Filing date: 2002-03-18
Publication date: 2002-09-26
Also published as: EP1370409B1; US20020175445A1; ES2269739T3; DE60213074D1; CN1494477A; JP2005505436A; US7037456B2; CZ20032242A3; EP1370409A1; DE60213074T2; ATE332800T1; WO2002074523B1

Abstract

Plant for the production of flexible tubes (5), comprising a skirt (1), a head with a neck and a shoulder connecting said neck to said skirt. Said plant comprises a first zone for the production of said skirts, a second zone for the production of the flexible tubes, a third zone for the finishing of the flexible tubes produced as above, a first transport means (100), for transporting said skirts in a continuous movement from said first zone to said second zone and a second transport means (300) for transporting in a continuous manner, synchronised with the previous movement, said tubes from said second zone to said third zone. The second zone comprises a third transport means (10) for transferring the dies (210) in a continuous movement, synchronised with that of the first transport means (100) and with that of the second transport means (300), charging means (280) for charging the skirts (1) on the dies (210), associated with the synchronised movement of said first and third transport means and discharging means for releasing the dies (210) from the tubes (5) which top them, associated with the synchronised movement of said second and third transport means.

Description

WORKSHOP FOR THE MANUFACTURE OF FLEXIBLE TUBES IN PLASTIC MATERIAL WITH MOLDING OF THE HEAD ON THE SKIRT CARRIED OUT BY TOOLS

CONTINUOUS MOVEMENT

TECHNICAL AREA

The invention relates to a workshop for manufacturing flexible tubes intended for storing and distributing fluid to pasty products, such as cosmetic products, pharmaceutical products, hygiene products or food products. The flexible tubes concerned have a head made of plastic material (s) and a cylindrical skirt (axisymmetric or not) essentially comprising one or more layers of plastic materials, possibly with a thin intermediate metallic layer.

STATE OF THE ART

In general, a flexible tube is produced by assembling two parts manufactured separately: a flexible cylindrical skirt of given length (typically 3 to 5 times the diameter) and a head comprising a neck with dispensing orifice and a shoulder connecting said neck to the cylindrical skirt. The head made of plastic material (s) can be molded separately and then welded to one end of the skirt, but the latter is advantageously molded and welded autogenously to the skirt using either an injection molding technique (FR 1 069 414) or a compression molding technique for an extruded blank (FR 1 324471).

In these two techniques, the skirt is fitted around a punch, one of its ends protruding slightly from the end of the punch, said punch end serving as a mold for producing the internal surface of the tube head (inside of shoulder and neck). In these two techniques, a matrix is used which is pressed against the end of the punch, the imprint of this matrix defining the outer surface of the shoulder and the neck. The main difference between these methods lies in the fact that these tools are first pressed firmly against each other before the injection of the plastic in the first case and that it is their mutual approach which causes compression. of an extruded blank in the second case.

In both cases, the end of the skirt projecting from the punch is trapped in the cavity delimited by the end of the punch and the imprint of the die. The plastic material - under the effect of injection or under that of compression - comes into contact with the end of the skirt and, being at a temperature above their respective Vicat softening points, the plastic materials of the head and skirt are welded together without further heat or material. After a slight pressure maintenance (of the order of a few seconds) and cooling, the head is molded into the desired dimensions and welded firmly to the skirt.

PROBLEM

The previous techniques, which appeared around fifty years ago for the first and around forty years ago for the second, have been regularly improved. They currently allow production rates close to 200-250 units per minute. But it seems that we are now reaching the limit and that a significant increase in production rates (beyond 250-300 units per minute) can no longer be obtained by simply adapting existing devices. The Applicant therefore sought to create a new workshop for manufacturing flexible tubes designed to obtain significantly higher production rates under acceptable economic conditions.

OBJECT OF THE INVENTION

The object according to the invention is a workshop for manufacturing flexible tubes comprising a skirt and a head provided with a neck and a shoulder connecting said neck to said skirt, said workshop comprising three distinct operational zones,

the first zone being assigned to the manufacture of said skirts, typically comprising a device for shaping a long cylindrical sleeve at the outlet of which the skirts are cut from the sleeve to the desired length,

the second zone being assigned to the manufacture of flexible tubes, comprising at least one device for manufacturing plastic blanks and several devices for molding the heads by compression of said blanks, each molding device comprising a die and a punch, each punch being provided before molding with one of said skirts so that, once molded, the head is welded to said skirt, - the third zone being assigned to the completion of the flexible tubes thus produced, said workshop also comprising

- a first transfer means, transferring in continuous movement said skirts from said first zone to said second zone, - and a second transfer means transferring, in a continuous movement synchronized with the previous one, said tubes from said second zone to said third zone , said workshop being characterized in that the second zone comprises a third transfer means transferring the punches in a continuous movement synchronized with that of the first transfer means and with that of the second transfer means and in that the second zone also comprises loading means, loading the skirts on the punches, associated with the synchronized movement of the first and third transfer means, and unloading means, releasing the punches from the tubes which cap, associated with the synchronized movement of the second and third transfer means.

The first zone typically comprises a device for shaping a long cylindrical sleeve and means for cutting the skirts in this sleeve. The cylindrical sleeve is "long", in the sense that its length is significantly greater than that of the skirts. It is for example an extruded or coextruded plastic sleeve, the plastic material (s) being continuously supplied by one (several) screw extruder (s). It may also be a sleeve produced by rolling and longitudinally welding a strip comprising one or more layers of plastic material - and possibly a thin intermediate metallic layer. The strip is rolled locally in order to bring its lateral edges opposite, then said lateral edges are welded after having them juxtaposed or joined. This produces a long cylindrical sleeve running in the direction of its axis.

The end of the long cylindrical sleeve is then cut discontinuously to obtain a skirt of the desired length, preferably using one or more cutting tools. These cutting tools accompany the advance movement of the long cylindrical sleeve so that they cut the wall of said long cylindrical sleeve in a plane remaining perpendicular to the axis of said long cylindrical sleeve. Once cut, the skirts remain in the axis of the long cylindrical sleeve and push each other, under the effect of the advance of said long sleeve, to a place where they are removed by the first transfer means. The first transfer means has individualized withdrawal means, typically rods intended to be fitted by the skirts, which move in a continuous movement which allows them to arrive at the same place with regard to the end of a new skirt. each time the long cylindrical sleeve advances a length of skirt. Said first transfer means in continuous movement transfers the skirts from the first zone to the second zone. It imposes on each skirt a movement such that the axis of the skirt is not tangent to the path described by this movement. Preferably the axis of the skirt always remains substantially perpendicular to said trajectory. Preferably also, so that all of the skirts remain in a position close to an average position, rods with a diameter fairly close to the diameter of the skirt are chosen. Such rods will hereinafter be called "loading mandrels".

The second zone according to the invention is assigned to the manufacture of flexible tubes. It comprises a loading area for the skirts on the punches, in which loading means act between the first transfer means and the third transfer means, an area for manufacturing plastic blanks, an area for manufacturing tubes by compression molding of the heads on the ends of the skirts fitted around the punches, and an unloading area for the tubes thus produced, in which unloading means act between the third transfer means and the second transfer means. The third transfer means transfers the punches to the loading area of the skirts, the tube manufacturing area and the tube unloading area. The description of these different areas will be detailed below.

The second transfer means continuously transfers the tubes from the second zone to the third zone. It imposes on each tube a movement such that the axis of said tube is not tangent to the path. Of preferably the axis of said tube always remains substantially perpendicular to said path. Typically, this second transfer means can be a continuous chain with buckets. The cups are hollow receptacles intended to collect the tube, their cylindrical cavity having a diameter slightly greater than that of the tubes. Said cylindrical cavity is generally provided with through channels in which air is circulated either by suction to keep the tube coaxially with said cavity or by blowing to eject said tubes.

The second transfer means is said to be synchronized with the first transfer means in the sense that it makes it possible to debit a flow of tubes leaving the second zone identical to the flow of skirts entering the second zone. In this way, there is neither accumulation nor exhaustion of the batch of skirts (and therefore of tubes) crossing the second zone. To give flexibility to the smooth running of the workshop,. the first and second transfer means are also provided with accumulation means making it possible to temporarily continue (a few minutes at most) an upstream operation when a downstream operation cannot be carried out.

The movement of the first transfer means, the movement of the second transfer means and the movement of the third transfer means are said to be "continuous" in the sense that at no time, in particular during the loading of the skirts, during the compression of the head and during the unloading of the tubes, the skirts or the tubes are not kept stationary. Preferably, the movement of the dies is also continuous and follows the general movement imposed by the third transfer means.

The third zone is assigned to the completion of the tubes. In general, there are a certain number of additional operations to be carried out on the tube, once the head has been molded on the end of the skirt. These operations can be: fixing a closure cap, printing the skirt, depositing an exterior varnish, etc. The finishing stations can be grouped into devices (for example capping machines) which are supplied with tubes by the second transfer means.

Let us return in detail to the description of the second zone.

The second zone includes a loading area in which loading means transfer the skirts in a continuous movement so that they leave the first transfer means and fit around the punches animated by the movement imposed by the third. means of transfer

The synchronization of the continuous movement of the punches with that of the first means for transferring the skirts is such that, in said loading area, the punches and the skirts follow parallel trajectories while their axes arrive substantially in coincidence. When they arrive substantially in coincidence, a loading means attached either to the first transfer means or to the third transfer means, imposes on a skirt a relative movement of axial translation in the direction of the punch so that the skirt is fitted with a slight play in the punch through its first open end, said relative translation being stopped when said skirt is almost entirely fitted around the punch, one of its ends intended to be welded to the head, projecting from the head of the punch. Preferably, this loading means is attached to the third transfer means, which makes it possible to keep a simple chain with loading mandrels - as a means of transferring the skirts.

In cases where the duration of the molding operations is particularly long (manufacturing requiring several successive compressions, for example example: production of multilayer heads or even overmolding of a plug), it is possible to provide several third transfer means which would each transfer a plurality of punches and would bring them into the same loading area where several loading means would act simultaneously to supply the punches moved by the various third transfer means in skirts of the first transfer means. However, in the most frequent case, the time necessary for the compression, the maintenance under stress and the cooling of the head is sufficiently short so that a single third means of transfer suffices.

In the tube manufacturing area, there are several devices for molding heads animated by the continuous movement of the third transfer means. The number of these devices is defined as a function of the target rate and of the duration necessary for compression and cooling with constrained holding of the molded part (of the order of a few seconds, typically 5 seconds for a current head geometry flexible tube). These devices circulate in closed loop (s) which do not necessarily coincide: the loop of punches and the loop of dies. In the manufacturing area, the punch and the die follow, thanks to the third transfer means, a general or overall continuous movement synchronized with that of said first and second transfer means. This movement is said to be general since the punch and the die must move relative to each other, on the one hand to effect compression, on the other hand, at the end of compression, for the first phase of demolding which consists in moving the matrix away from the punch remaining "capped" by the tube.

The punches are moved by the third transfer means which circulates them in the loading area of the skirts, in the manufacturing area and the unloading area to return to the loading area. The dies have a movement imposed at least in the manufacturing area by the third means transfer which drives the movement of the punches but they must also, outside the manufacturing area, move away enough from said punches to allow the establishment of the plastic blank for the next compression. Preferably, to facilitate the alignment of the axes of the punches and those of the dies, the dies remain integral with the third transfer means even outside the manufacturing area. The relative distance of the punches with respect to the dies takes place in a direction perpendicular to the common direction of the axes of the punches and the dies and to the path imposed by the third transfer means.

In the manufacturing area, the molding devices each comprise a die and a punch already equipped with a skirt, said skirt then being fitted around the punch, one of its ends projecting slightly from the head of said punch. The die and the punch are aligned along their common axis and the air gap is occupied by the blank. The blank is a piece of extruded thermoplastic material which is deposited either in the cavity of the die or on the end of the punch. The deposit is made either in the process at the extrusion outlet - in this case, the preform has a compact shape, preferably axisymmetric - or using another transfer means, i.e. a fourth transfer means transferring the blanks in a continuous movement synchronized with the third transfer means or a fifth transfer means transferring the blanks in a discontinuous movement, that is to say allowing their reception in stationary receptacles which are then placed in movement so as to be able to deposit the blanks in the air gap of the molding device driven by the third transfer means.

The head of the punch has a shape intended to define the interior surface of the tube head. The imprint of the matrix defines the outer surface of the head. The punch is, in the manufacturing area, fitted with the skirt, fitted around it at a height such that the end of the skirt slightly protrudes from the punch head: typically, 3 to 4 millimeters beyond the shoulder serving as a basis for the substantially frustoconical shape of the head of the punch which defines the shape of the inner surface of the shoulder of the tube to be produced. So that the skirt remains in this position until the molding, the punch is provided with one or more elastic elements with radial displacement offering a cylindrical size whose diameter is, at rest, greater than that of the skirt.

When the punch and the die are aligned, when the air gap between the head of the punch and the imprint of the die is filled by the blank, the temperature of which is in the range or slightly above the setting temperature in use, the punch and the die are brought closer, preferably by relative translation from one to the other along their common axis. The relative translation means acting on the punch (respectively the matrix) is associated with the third transfer means and imposes a translation perpendicular to the trajectory of the matrix (respectively of the punch).

Under the effect of this translation, the blank deforms and the flow of plastic material is guided by the free surfaces of the residual air gap which gradually decreases in volume. When the punch and the die are joined, they define a mold cavity where the end of the skirt is trapped. The plastic of the blank comes into contact with the end of the skirt. The plastics of the head and the skirt are welded together without further heat or material. They remain welded together after a slight pressure maintenance and after cooling. The compression causing significant efforts, the molding tool which is not subjected to translation is preferably supported by a support means over the entire part of its path during which the other molding tool approaches then remains united.

The second zone also includes an unloading area in which unloading means transfer in a continuous movement the tubes fitted around the punches, animated by the movement imposed by the third transfer means, to the second transfer means.

The synchronization of the continuous movement of the third transfer means with that of the second transfer means is such that, in the unloading area, the punches provided with the tubes and the buckets follow parallel trajectories while their axes arrive substantially in coincidence. When they arrive substantially in coincidence, an unloading means attached either to the third transfer means or to the second transfer means, imposes on the tubes a relative movement of axial translation in the direction of the bucket so that the tube is collected in the cavity of the bucket. Preferably, this unloading means is attached to the punch transfer means, which makes it possible to keep a simple chain with buckets as a second transfer means.

Synchronization implies that the flow of tubes leaving the second zone is equal to the flow of skirts entering the second zone. There is nothing to prevent, in the cases where the molding operations are particularly long, to provide several third transfer means which would each transfer a plurality of punches and would bring them into the same unloading area where several unloading means would act simultaneously to strip each punch from each loop and feed the second transfer means in tubes from the various third transfer means.

When attached to the third transfer means, the loading means and the unloading means can coincide with means capable of performing relative translation in both directions, thereby fulfilling the two functions. However, preferably, the skirts being very flexible and difficult to handle by their cylindrical wall, two different means are used: the first is for example a pusher finger (or fork), pushing one end of the skirt towards the punch and the second can simply include a pipe formed in the punch, opening in one or more places of the head of the punch and through which a jet of compressed air is passed. An overpressure is exerted on the internal face of the tube head, sufficient to detach said tube head from the punch head and then eject the tube axially in the direction of the bucket.

The second zone also includes the area for manufacturing the blanks. This is not necessarily affected by the continuous movement imposed according to the invention by the third transfer means. The blanks can, for example, be obtained "statically" by extrusion, then removed and deposited on the passage of a die or a punch. However, to facilitate compression of the head, it is often advantageous to start from an already axisymmetric blank. Thus, a toroidal blank makes it possible to fill the molding cavity of the head with more regularity. It is preferable to seek to preserve the shape of such a blank until it is placed in the imprint of the die or on the punch head, around the protuberance defining the internal surface of the neck. This can be difficult if samples are taken at high speed parade and in this case we seek to deposit them in the air gap of the molding devices by following a continuous movement synchronized with that of the third transfer means, either by carrying out the extrusion with means moved by a fourth transfer means synchronized with the third transfer means or by carrying out the extrusion "statically" and using a fifth transfer means transferring in a discontinuous movement of the blanks thus extruded by means of receptacles statically receiving the extrudates and then set in motion so as to be able to deposit the blanks in the air gap of the molding device driven by the third transfer means.

In the first case, the extruded blank leaves a stationary extrusion die supplied by a fixed extruder (fixed, in the sense that only the extrusion screw rotates about its axis). It is for example deposited in the imprint of the matrix, while the latter, moved by the third transfer means, moves in the vicinity of the outlet of the die to collect the blank in passing. In a simple embodiment, the extruded blank comes out horizontally continuously and a scraper finger located above the matrix shears the extrudate which falls by gravity into the imprint of the matrix. The speed of movement of the dies - and of the associated scraper fingers - and the speed of extrusion of the extrudate in thermoplastic material are defined so that the blank obtained by shearing the extrudate has the desired quantity of thermoplastic material, allowing filling with good precision (manufacturing deviations must typically be less than 5%) the volume of the molding cavity.

One can also modify the die outlet so that the extrudate comes out vertically and use a slide valve releasing and closing the die outlet. The sliding of the drawer shears the extrudate to the desired length and the extrudate obtained falls into the imprint of the matrix which is circulated below, vertically from the outlet of the die. From this blank, it is therefore a question of making a tube head comprising a shoulder - one end of which is welded autogenously to one end of the skirt - and a neck, the neck being provided with a dispensing orifice. . The production of the neck provided with its dispensing orifice poses a certain number of problems when the molding is carried out by compression, problems exacerbated when using tools in continuous movement: either a solid extruded nut is used as a blank and in this case it is very difficult to avoid the formation of a residual veil covering the orifice, or a toroid-shaped blank is used which is fitted around a central protuberance linked to the die or the punch.

If you use a solid nut-shaped blank, you almost always get a residual haze in place of the hole. Even if a fitting system is provided, for example a protuberance of the punch coming into engagement in a cavity of the die, it is not possible to impose a tight fit and perfect alignment of the tools, a partly because these conditions are not very compatible with moving tools and high production rates, and secondly because the pressure required at the end of compression becomes unacceptable.

If a toroidal blank is used, the problem is to produce the latter in the desired shape and then to put it in place without excessively deforming it in the air gap between the molding tools.

A first solution consists in producing toroidal blanks using mobile extruders. A fourth transfer means is then advantageously used transferring the extruded blanks in a continuous movement synchronized with the third transfer means. It may be a transfer means comprising several extruders driven by this same fourth transfer means which locally imposes on them a trajectory parallel to that punches or that of the dies intended to collect the blanks, the extrusion axis coming substantially in coincidence with the axis of the receiving tool, over a sufficient length so that the quantity of plastic material desired can be extruded.

A second solution consists in making the blanks with a stationary extruder. One or more fourth transfer means are then used transferring in a continuous movement intermediate receptacles collecting the blanks. This (or these) fourth (s) means (s) of transfer requires (s) a movement slow enough to be able to collect the drafts on parade in good conditions, each receptacle of each fourth means of transfer passing in front of the outlet of a stationary extrusion die. Using a stationary extruder, a thick cylindrical extrudate is produced which is sheared to a height such that the quantity of material required to obtain the tube head is obtained.

In a first variant of this solution, the extrudate is sheared and then collected in a receptacle provided with a perforating pin whose end comes to touch the die and which moves relative to said die so that the time necessary for browse the internal diameter of the central hole of the toroidal blank corresponds to the extrusion time to obtain the amount of plastic required.

In a second, preferred, variant of this solution, the shearing is carried out on passing by using a blade of particular shape secured to the fourth transfer means. This blade typically has a V shape which allows the extrudate to be sheared while obtaining a slightly deformed toroidal blank. This blade also acts as a receptacle after shearing of the extrudate and collects the toroidal blank thus obtained for the time necessary for its transfer to the compression molding tools. This or these fourth transfer means transfer (s) in a continuous movement the intermediate receptacles which collect the extruded blanks in a continuous movement synchronized with the third transfer means and the installation is carried out, by gravity and possibly with using an air jet, in the air gap between the molding tools, that is to say in the imprint of the die or around a central protuberance of the punch. A particularly simple and effective embodiment of this variant is presented in Example 3.

Another variant of this second solution consists in also using a fifth transfer means transferring in a discontinuous movement intermediate receptacles collecting the blanks when the stationary is complete, leaving a stationary extruder then setting them in motion to deposit the blanks in the air gap of the molding tools moved by the third transfer means. Such a means can for example be a bucket chain associated with an accumulator.

A third solution is to make a simple nut by extrusion: it does not prevent the formation of a veil obstructing the orifice during compression. On the contrary, it is done intentionally. We will name this veil below: "operculum" since it blocks the dispensing orifice. The cover is given a specific shape, such that it can then be easily detached without using a particular cutting tool, to obtain a dispensing orifice having sharp and clean edges.

In this third solution, the punch and the die have imprints drawn in such a way that the head thus molded has a neck, the upper end of which is surmounted by a cover which has at least one transverse wall which includes a breakable zone whose closed outline delimits the desired shape of the orifice and which is surrounded by two zones capable of withstanding the mechanical force necessary to break said breakable zone, one of them being intended to transmit said mechanical force and the other to serve as support.

After molding, said cover is removed by applying a mechanical force to a part of the cover. This part of the cover is separated from the breakable zone by the zone capable of transmitting said mechanical force. The application of said mechanical force has the consequences of breaking the breakable zone and obtaining the dispensing orifice. A particularly simple and effective embodiment, presented in Example 2, consists in giving a part of the cover a shape of an axial rod. Once the matrix released, the tube thus produced and provided with said cover is integral with the punch and moves in a continuous movement thanks to the third transfer means. It then suffices to place a simple stationary finger across the trajectory of the end of the stick, locating it at a distance such that the breakable zone is cooled to a temperature slightly lower than the glass transition temperature when the head tube reaches this position (it only takes a few seconds). The end of the stick is thus immobilized by the finger while the base of the stick continues its continuous movement. This results in a flexion imposed on the rod which is transmitted to the transverse wall. Under the effect of this bending, the breakable zone breaks and the cover is ejected, in a precise and reproducible direction, outside the production line in continuous movement.

Another object of the invention is a method of manufacturing flexible tubes comprising a skirt and a head provided with a neck and a shoulder connecting said neck to said skirt, said method comprising the following steps: - a first step in which skirts are animated with a continuous movement using a first transfer means

a second step in which said skirts are loaded using loading means on punches associated with a third transfer means animated by a continuous movement synchronized with the first transfer means, one of the ends of the skirts slightly protruding from the punches;

- A third step in which the flexible tubes are produced by molding the head with autogenous welding on one end of the skirt, the head being obtained by compression molding of a blank, by relative approximation of the punch provided with the skirt and a matrix, said punch and said matrix defining when they are joined a mold cavity where the end of the skirt is trapped, said punch and said matrix being animated by a continuous overall movement associated with the third transfer means, said blank being deposited before compression in the air gap between the punch and the die using a fourth transfer means animated with a continuous movement synchronized with the third transfer means;

- A fourth step in which said tubes are unloaded using unloading means on a second transfer means animated with a continuous movement synchronized with the third transfer means.

The method is described here from the time when the skirts are already made and until the time when the tubes are sent to finishing operations. The steps of the method according to the invention can obviously be enriched by the preferred characteristics described above. The punches are said to be "associated" with the third transfer means in the sense that, like the dies, they are animated by a continuous overall movement corresponding to that of the third transfer means but they are also animated by a relative movement intended for approximation or distance with the matrix, or when loading the skirts or when unloading the tubes.

It is also possible to envisage certain variants, for example the use of several elements already produced and their assembly by compression molding of an intermediate part and autogenous fusion or imprisonment of a part of these elements with the part molded by compression: it is thus possible provide the punch with an insert disposed on its end, said insert being intended to cover the internal surface of the shoulder to increase the diffusion barrier at this location. Such inserts are for example described in US 4,466,284 (KMK), EP 0 130 239 (AISA) or EP 0 724 897 (CEBAL S.A.). The head is compression molded as previously described. The mold cavity is designed so that the insert is trapped at its ends by the plastic of the compression molded head. Nothing obviously prevents that the punch is also provided with the skirt, fitted around its cylindrical surface, and that there occurs, simultaneously with the trapping of the insert, an autogenous welding of the end of the skirt with the material plastic of the compression molded head.

Another variant consists in providing the punch of the skirt and an already molded head but having an outside diameter slightly smaller than that of the skirt, and in producing the tube by compression molding of a toroidal blank intended to produce the only outer end of the shoulder, which constitutes the border zone between the head and the skirt, as indicated in US 6068717 (BA Schwyn). The plastics of the head, the skirt and the toroidal blank are compatible in fusion and the ends of the head and of the skirt are sufficiently thin so that they melt in contact with the plastics of the blank and become mix with it during compression molding of said blank. Finally, this process can be generalized to the manufacture of assemblies other than flexible tubes, namely assemblies of parts made of plastic material (s) of which at least one part has a part which is welded autogenously to a last part during the molding of this last part or even trapped by the plastic of said last part. It suffices to provide one and / or the other with compression molding tools animated with a continuous overall movement with parts already produced and some parts of which protrude so that when the molding tools are joined together, they define a molding cavity in which these parts are trapped. The protruding parts may be parts that are thin enough to melt in contact with the plastic of the blank intended to make the last part and mix with said plastic during compression molding of said blank. However, the protruding parts can also be massive protruding parts, in the form of a dovetail or any other form of anchoring, so that they remain trapped by the plastic material of the last part after molding of the latter by compression.

The different parts of the assembly can be made from the same material or from compatible molten materials if an autogenous weld is sought during compression molding. They can also be incompatible in fusion and in this case, one will seek a trapping of certain parts of the parts already produced by the plastic of the part molded by compression.

Compression molding can also be replaced by a simple conformation of one of the parts of the assembly which is made of a polymeric material having adhesive properties. Preferably this part is an intermediate part between two parts already molded like the blank O-ring intended to constitute the border zone between head and skirt described in US 6,068,717. The shaping tools are identical to the compression tools described above. The supply of tools and the installation of parts on these tools is also identical. As the polymeric material having adhesive properties, a polyolefin modified with butyl or butylene radicals can be chosen.

PARTICULAR EMBODIMENTS OF THE INVENTION

In the preferred embodiments of the invention presented below, the second zone is occupied by a device comprising the third transfer means, the latter animating the movement of the punches as much as that of the dies. Said device is illustrated in FIGS. 1, 2, 3 and 11. FIGS. 4 to 8 illustrate the different stages of loading, compression and unloading. Figures 9 to 11 illustrate various means for obtaining and placing a blank in the air gap of the molding tools.

FIG. 1 illustrates in perspective view a rotary press occupying the second zone of a workshop according to the invention, with in the foreground a part of the supply chain for the skirts entering, scrolling and leaving the loading zone and in the second plane part of the bucket chain fitted with tubes at the outlet of the unloading area.

FIG. 2 illustrates in perspective view the press of FIG. 1, observed from a point roughly diametrically opposite to the observation point of FIG. 1, with on the left part of the supply chain for the skirts, on the right part of the bucket chain collecting the tubes and, in the middle, the part of the press dedicated to compression molding of the heads on the skirts. Figure 3 illustrates a top view of the same rotary, the supply chains of the skirts and tube transfer.

Figure 4 details the various elements involved in the compression of the head on the skirt. In this figure, as in the following ones, the skirt, the matrix and the tube produced are represented with a quarter removed so as to be able to illustrate the interior of the matrix, the rod of the perforating pin and, optionally, the punch.

Figures 5 to 8 illustrate different stages of compression:

Figure 5 shows the fitting of the skirt around the punch.

Figure 6: presents all the tools at the time of the removal of the blank in the matrix

Figure 7 illustrates the start of compression

Figure 8 shows the tube obtained when it is ejected into a cup.

Figure 9.1 illustrates the shape of the tube head obtained in Example 2: once compression molded, it does not have an orifice but a veil provided with a breakable zone such as after tearing of said breakable zone , we obtain an orifice delimited by a clean edge without burrs.

Figure 9.2 shows in detail a section of said breakable zone. Lα figure 9.3 illustrates other tubes having a head different from that presented in 9.1 and presenting a T-shaped cover which is trapped in a rail not tangent to its trajectory.

FIG. 10 illustrates the V-shaped blade which also serves as a receptacle used in example 3

Figure 11 illustrates the transfer device used in Example 3

EXAMPLE 1 (Figures 1 to 8)

The workshop includes three separate operational areas, only the second of which is illustrated in Figures 1 to 3.

The first zone is used for the manufacture of skirts 1. The long cylindrical sleeve, 30 mm in diameter, is produced by longitudinal welding of the rolled edges of a ribbon in a multilayer structure with a barrier effect PE.BD / PE.HD / EAA / EVOH / EAA / PE.BD which we scroll continuously. The ribbon is already printed and the skirts 1 are cut at the desired length, 160 mm, while respecting the position of the printed decoration. They are then fitted around the loading mandrels 110 of the first transfer means 100 which is a chain with loading mandrels.

The second zone comprises a device for manufacturing the blanks 30 and a rotary press 10 putting in a continuous circular movement R all of the molding devices 200, comprising the mandrels 210 and the dies 240 and the loading means 280 and the unloading means .

The third zone is occupied by a corking installation. The first transfer means 100 is a chain with loading mandrels 110. It continuously transfers the skirts 1 from the first zone to the second zone.

The second transfer means 300 is a bucket chain 310. It continuously transfers the tubes 5 from the second zone to the third zone.

The second zone comprises a third transfer means: the rotary 10 which transfers the punches 210 in a continuous movement synchronized with that of the mandrel chain 100 and with that of the bucket chain 300. The second zone also comprises loading means 280, loading the skirts 1 onto the punches 210, associated with the synchronized movement of the press 10 and the chain with loading mandrels 100, and unloading means, releasing the punches from the tubes 5 which cover them, associated with the synchronized movement of the rotary and bucket chain 300.

The press 10 rotates about a vertical axis 11 and comprises a number of molding devices 200 (20 in this case) which move in an overall rotational movement (R). The axes of the skirts 1, the axes of the punches 210, the axes of the dies 240 and the axes of the tubes 5 remain parallel to each other and to the axis of rotation 11 corresponding to the common continuous circular movement R. The punches 210 can move axially towards the die 240 for molding the head or in the opposite direction to release the tube 5 thus produced. The die 240 can move radially to collect the blank 20 over a given diameter, different from that of the cylinder on which the trajectory of the punch rests. The means for loading the skirt 1 on the punch 210 is a loading fork 280, acting as a pusher on a clothing 120 secured to the loading mandrel 110 of the chain to loading mandrels 100. This fork 280 is actuated to move axially in the direction of the punch 210 while the die 240 is on a different diameter to collect an extruded blank 20.

The punches 210 can be axially translated by means of cam followers 220, in this case rollers, situated at the ends of the punches opposite their heads 230, which follow during the general rotation R a path of fixed cam having a non-planar raceway, imposing a displacement of the punch towards the die in the zone of manufacture of the tubes. The cam track is not shown directly in Figures 1 and 2 but it is materialized by the different positions of the ends of the punches 210. An elastic system - also not shown - keeps the rollers 220 in permanent contact with the track cam. The punch 210 is long enough to be able to present, between the end of the skirt 1 almost entirely fitted and the roller 220 intended to follow the raceway, a cylindrical portion 215 which slides in a sleeve integral with the press 10 and which ensures the firm hold of the punch parallel to the axis of the general rotation.

The dies 240 follow the same general rotational movement R. Carried by die holders 250 which can be actuated radially, they can collect the extruded blanks on a diameter different from that of the punches. For reasons of space, this diameter is greater than the diameter of the trajectory of the punches.

In the case illustrated by this example, the die 240 collects in passing a toroidal blank 20 produced by an extruder 30, the die outlet of which is oriented vertically. A perforation pin 270 has an axial rod 271 which facilitates the centering of the toroidal blank in the cavity of the die 240 and assists in the shaping of the dispensing orifice provided the end end of the neck. The rod slides in the bore of the matrix and the friction of the rod in the bore is sufficient to keep the pin 270 integral with the matrix 240. A shallow bore is also provided in the central end 235 of the head 230 of the punch 210. In this way, at the start of compression, the upper end of the rod 271 of the perforation pin 270 enters the interior of this bore, which makes it possible to have, after molding, a neck having an orifice distribution system with a clean outline and no residual haze.

Entering the manufacturing area, the die carriers are actuated so that they perform a centripetal radial movement. The dies are thus brought back to the vertical of the punches. The compression is carried out by vertical lowering of the punch in the direction of the die. The matrix and matrix holder assembly scrolls above a ramp which will serve as support throughout the course during which the compression takes place.

A hole 260 with a diameter greater than that of the skirts is provided in the die holder so that the skirt 1 can be fitted, using a loading fork 280, around the punch 210 while the die 240 collects the plastic blank 20. In the loading area, a clothing member 120 sliding freely around the loading mandrel 110 meshes in the concave space of the loading fork 280.

A common continuous circular motion R is imposed which passes the punch 210, the die holder 250, the die 240 and the loading fork 280 successively into the loading area of the skirts (I), then into the manufacturing area tubes by molding the heads on the skirts (II), then in the unloading area (III) of the tubes thus produced to return in a new cycle to the loading area for the skirts (I). In the tube manufacturing area (II), several molding devices 200 each include a die 240 already provided with the extruded blank (not shown in the figures) and a punch 310 already fitted with a skirt 1 fitted around said punch, one of its ends projecting slightly from the head 230 of said punch.

The head 230 of the punch 210 has a shape intended to define the interior surface of the tube head. The imprint of the matrix defines the outer surface of the head. When the punch 210 and the die 240 are joined, they define a molding cavity where the end of the skirt is trapped. The plastic material of the blank - under the effect of the approximation of the punch 210 and of die 240 - comes into contact with the end 3 of the skirt which projects beyond the mandrel 210. The plastic materials of the head and of the skirt weld intimately with each other without further heat or material.

The chain 100 with transfer mandrels 110 and the chain 300 with buckets 310 have a synchronized movement in the sense that they allow the same flow of skirts and tubes to be cut and that there is neither accumulation nor exhaustion of the batch. skirts (and therefore tubes) crossing the second zone. The movement of the chain 100 with transfer mandrels 110, of the chain 300 with buckets 310 and of the rotary press 10 are continuous in the sense that at no time, especially during the loading of the skirts, during the compression of the head and during the unloading of the tubes, the skirts or the tubes are not kept stationary. In the present case, the movement of the dies 240 is also continuous and follows the general movement imposed by the press 10.

The second zone comprises a loading area (I) in which loading means 280 transfer the skirts 1 in a continuous movement so that they leave the chain 100 with loading chucks 110 and that they are fitted around the punches 210 animated by the movement R imposed by the press 10.

The synchronization of the continuous movement of the punches 210 with that of the chain 100 is such that, in the loading area (I), the punches 210 and the skirts 1 follow parallel trajectories while their axes arrive substantially in coincidence. When they arrive substantially in coincidence, a loading fork 280 attached to the press 10, meshes around a clothing 120, which is a ring sliding along the loading mandrel 110 and on which the skirt 1 is placed. It is actuated vertically upwards and pushes the clothing unit 120 so that the skirt 1 follows a relative movement of axial translation in the direction of the punch 210. The skirt 1 is fitted with a slight play around the punch by its first end. open 2, said relative translation being stopped when said skirt is almost entirely fitted around the punch, its second end 3, intended to be welded to the head of the tube, projecting from the head

230 of the punch.

The second zone also includes an unloading area (III) into which unloading means transfer in a continuous movement the tubes fitted around the punches, animated by the movement imposed by the press 10, towards the chain 300 with buckets 310. The forks of load 280, inactive in this area, mesh around the narrowed base 315 of the buckets.

The synchronization of the continuous movement of the rotary press 10 with that of the chain 300 with buckets 310 is such that, in the unloading area (III), the punches 210 provided with the tubes 5 and the buckets 310 follow parallel trajectories while their axes arrive substantially in coincidence. When they arrive substantially in coincidence, air is blown under pressure into a cαnαlisαtion formed in the punch 210, which opens in one place of the head 230 of the punch 210. An overpressure is exerted on the internal face of the tube head, sufficient to detach said tube head from the head 230 of the punch then eject the tube 5 axially in the direction of the bucket 310.

The particular embodiment illustrated in this example is a prototype, intended to verify the functionalities of the various parts of the workshop and in particular of the press 10. This prototype was not designed to achieve significant production rates but we describe thereafter the various actions envisaged to achieve rates of the order of 350 tubes / minute.

Equipped with 20 punches which move over a diameter of 600 mm, rotating at the speed of 6 revolutions / min, the press 10 of this example allows 130 tubes to be produced per minute.

The blank, in PE.BD, is produced using a screw extruder with vertical outlet pointing downwards. It has a toroidal shape with an external diameter of 20 mm and an internal diameter slightly greater than 10 mm. It weighs about 3 grams. It is deposited in the imprint of the matrix which scrolls on a circular trajectory with a diameter of 700 mm in order to take the said blank on parade.

The pressure on the molding tools and the cooling time last approximately 5 s

To achieve higher rates, you can have several presses of the same type as the press described above and working in parallel. We can also design a larger press. For example, a rotαtive fitted with 40 molding devices, the punches moving over a diameter of 1300 mm, would make it possible to obtain a rate of 350 tubes / min.

At this rate, the blank positioning system must be replaced by a more complex system, for example a rotary press driving 4 extruders with a diameter of 600 mm and rotating at 20 revolutions / min, each extruder being capable of moving radially , so that the die and the die can run one above the other at the same speed over a length of at least 50 mm.

Optionally, the third zone can also be equipped with a rotary press provided with compression molding devices similar to that presented in the example above, but which would be devoted to the compression molding of the closure caps, according to the method described in French application FRO 1-2574 filed on 02/26/2001 by the plaintiff and whose examples concerning the neck - capsule assembly are incorporated by reference into the present application.

A second bucket chain collects the tubes 5 as they are contained in the buckets 310 so that the tubes are presented with their open end facing upwards in the loading area. A loading fork similar to the fork 280 - but with different dimensions adapted to the tube - takes the tube by its shoulder and imposes on it a relative translational movement towards a punch similar to the punch 210 described above. The matrix, the imprint of which defines the external surface of the stopper, is fed with a blank having a simple shape of a nut, taken in the process at the outlet of an extrusion die. The approximation of the punch and the die results in a compression of the plastic nut between the imprint of the die and the external surface of the neck which has just been molded. The capsule is thus produced by overmolding, the surface of the neck participating in the definition of the molding cavity. The neck and the capsule, for example provided with complementary short and shallow screw threads, offer the possibility of having a particularly tight closure and easy to unscrew.

Finally, these operations of molding the cap on the head do not require any intervention inside the tube, it is possible not to equip the third zone but the second zone with an additional rotary press. In such a case, the third transfer means would be a chain transporting the punches from the press manufacturing the tubes to that making the plugs. This avoids unnecessary operations of unloading, transfer from a bucket chain to another bucket chain to turn the tubes and then loading said tubes on a new chain with loading mandrels, the latter bringing the tubes to the 'loading area of the press intended for the overmolding of the capsules. On the other hand, the chain lengthens and the number of punches moved by the third transfer means is higher.

EXAMPLE 2 Moors 1 to 8 and Figure 9.1 and 9.2: variant Figure 9.3)

The workshop in this example presents all the means presented in the previous prototype example with the exception of the tube manufacturing area (II) which has been slightly fitted out to simplify the implementation of the blank and thus improve the production rates obtained.

In this example, the punch and the die have imprints such that the head 901 thus molded has a neck 903 _. whose upper end is surmounted by a cover 904 which has at least one transverse wall 905 which comprises a breakable zone 906 whose closed outline delimits the desired shape of the orifice and which is surrounded by two zones capable of withstanding the mechanical force necessary to break said breakable zone, one 907 of them being intended to transmit said mechanical force and the other 908 to serve as support.

A part 909 of the cover 904 has the shape of an axial rod. Once the matrix has been released, the tube thus produced and provided with said cover is integral with the punch 210 and moves in a continuous movement on the rotary press 10. It is then sufficient to place a simple stationary finger, one end of which (symbolized by the dashed circle) 910) is located on the path of the end of the stick 909. This finger is placed at a distance such that the breakable zone 906 can be cooled to a temperature close to 100 ° C. When the tube head 901 reaches this position (it only takes a few seconds), the end of the stick is thus immobilized by the finger while the base of the stick continues its continuous movement integral with the movement of the press 10. This results a flexion imposed on the rod 909 which is transmitted to the transverse wall 905 which is perpendicular thereto. Under the effect of this flexion, the breakable zone 906 ruptures and the cover is ejected. The cover then follows a tangential trajectory which ejects it outside the press area and is collected in a bin.

The break is made all the more cleanly as the speed of movement in front of the stationary finger is high. We observed that with a running speed of the order of 0.8 m / s, very good results were obtained.

The breakable zone 906 is located on the transverse wall 905. It is notched with a notch, the section of which is oriented in a direction that is slightly inclined relative to the axis of the neck. The notch preferably has a V shape, the bisector of the V is slightly inclined relative to the axis 1000 of the neck and describes a cylinder or cone with a center angle less than 90 °. The angle of the V is between 30 and 90 °, typically between 40 and 50 °. The V does not necessarily have its branches symmetrically around its bisector 963. Said bisector 963 makes an angle between 0 and 45 ° with the axis of said neck. In this particular example, the breakable zone is notched with a V-shaped notch, with an internal branch 961 which makes the axis 1000 an angle less than 5 °, an external branch 962 which makes with said axis an angle less than 55 ° and the bisector 963 of the V which makes an angle of 25 ° with the axis 1000 of the neck.

In this particular example, the head 901 is molded with high density polyethylene. Its neck 903 has an external diameter of 11.5 mm and an average thickness of 1.5 mm (excluding screw thread). Outside the breakable zone, the transverse web has a thickness close to a millimeter. The stick 909 has a height of 10 mm, the residual thickness of the veil at the level of the breakable zone is 0.3 mm.

Once the cover has been ejected, the neck 903 has an orifice without burrs or local deformation of 7 mm in diameter.

The cover may in fact have other forms which cooperate with an immobile element, at least not following the continuous continuous movement, so that the rupture is triggered by the difference in movement between this element and the third means of transfer. Thus, Figure 9.3 illustrates tubes 920 obtained with a head having an axisymmetric cover with inverted T-shaped section, so that the cover has an annular groove. After molding the head, the dies are removed and the tubes remain attached to the punches. The lids are removed by simply trapping the ends of the T-shaped lids, their annular grooves coming to fit into a stationary rail 940 which is not tangent to the trajectory of the tube heads resulting from the movement R of the rotary press 10 and the possible axial movement of the punches 210. After removal of the lids, the tubes 5 have a head with a dispensing orifice having a sharp edge.

EXAMPLE 3 f Figures 1 to 8 and Figures 10 and 1

As in the previous example, the workshop has the same characteristics as those of Example 1, only the tube manufacturing area (II) differs to simplify the production and installation of the blank and thus improve production rates.

A thick cylindrical extrudate 805 is produced using the stationary extruder 800 which is sheared at a height such that the quantity of material required to obtain the tube head is obtained.

The shearing is carried out in the parade using a blade 821, integral with the fourth transfer means, and produced in an open container 825. This blade typically has a V shape, the angle of the V preferably being between 80 ° and 120 ° (in this particular case, it is close to 100 °). Such a blade shape makes it possible to shear the extrudate while obtaining a slightly deformed toroidal blank. We will say later that this blank is appreciably toroidal: there is not strictly speaking axisymmetry due to the flattening due to shearing but the oval remains slightly marked so that the blank thus produced can easily fit around the protuberance of the punch intended to make the inside of the neck. To improve this shape, it is possible to prevent the effect of flattening by giving the tubular extrudate a section that is not circular but elliptical, the major axis of the ellipse being in the direction of movement of the blade. This blade also acts as a receptacle 820 after shearing of the extrudate and collects the toroidal blank thus obtained for the time necessary for its transfer to the compression molding tools.

The turret 810 acts as the fourth transfer means and transfers in a continuous movement the intermediate receptacles 820 which collect the extruded blanks in a continuous movement synchronized with the press 10 which acts as the third transfer means and one proceeds to the setting in place, by gravity and with the help of an air jet, in the air gap between the molding tools, that is to say in the cavity of the die or around a central protuberance of the punch.

BENEFITS

• all tube shaping operations are carried out with mobile tools, which makes it possible to manufacture the tubes without dead time and to exceed rates of 300 tubes / min. These rates can increase significantly if the supply of blanks can be done with a fourth or fifth means of transfer.

- simpler devices, less noisy, easier to design, more economical to maintain, this advantage is already appreciable with rates similar to those obtained with the installations of the prior art.

• greater flexibility in the conduct of the manufacturing process: in the processes of the prior art, the manufacturing steps were carried out in discontinuous movement with imposed downtimes, difficult to modulate. It was necessary to index the installations working "step-by-step", with heavy mechanical parts, the durations of the static operations being necessarily multiples of the greatest incompressible downtime. Here, the movement is more fluid, we can better control the efforts (softer cam profiles). This limits the mechanical stresses generated by the various blows associated with manufacturing in discontinuous movement. All the workshop devices are mechanically arranged, which improves their reliability.

NOMENCLATURE

Claims

1) workshop for manufacturing flexible tubes (5) comprising a skirt (1) and a head provided with a neck and a shoulder connecting said neck to said skirt, said workshop comprising three distinct operational zones,

the first zone being assigned to the manufacture of said skirts,

the second zone being assigned to the manufacture of flexible tubes, comprising at least one device (30) for manufacturing blanks (20) of plastic material and several devices for molding (200) the heads by compression of said blanks, each device for molding (200) comprising a matrix (240) and a punch (210), each punch being provided before molding with one of said skirts, so that, once molded, the head is welded to said skirt, - the third zone being assigned to the completion of flexible tubes, said workshop also comprising

a first transfer means (100), continuously transferring said skirts from said first zone to said second zone,

- And a second transfer means (300) transferring, in a continuous movement synchronized with the previous one, said tubes from said second zone to said third zone, said workshop being characterized in that the second zone comprises a third transfer means (10 ) transferring the punches (210) in a continuous movement synchronized with that of the first transfer means (100) and with that of the second transfer means (300) and in that the second zone also comprises loading means (280), loading the skirts (1) on the punches (210), associated with the synchronized movement of said first and third transfer means, and unloading means, releasing the punches (210) from the tubes (5) which cover them, associated with the synchronized movement of said second and third transfer means.

2) Workshop according to claim 1 wherein said first transfer means (100) is a chain with loading mandrels collecting said skirts at the outlet of the first zone and imposing on each skirt a movement such that the axis of the skirt always remains substantially perpendicular to its trajectory.

3) Workshop according to claim 1 or 2 wherein the second zone comprises an area (I) for loading the skirts (1) on the punches (210), in which loading means (280) act between the first transfer means and the third transfer means, a manufacturing area (30) of plastic blanks, a manufacturing area (II) of the tubes (5) by compression molding of the heads on the ends of the skirts fitted around the punches, and an unloading area (III) of the tubes thus produced, in which unloading means act between the third transfer means and the second transfer means, and where said third transfer means transfers the punches into the loading area ( I) skirts, the manufacturing area (II) of the tubes and the unloading area (III) of the tubes

4) Workshop according to any one of claims 1 to 3 wherein the second transfer means is a bucket chain transferring in continuous movement the tubes from the second zone to the third zone by imposing on each tube a movement such as the axis of said tube always remains substantially perpendicular to its path.

5) Workshop according to any one of claims 1 to 4 wherein the first and second transfer means (100, 300) are also provided accumulation means making it possible to temporarily continue an upstream operation when a downstream operation cannot be carried out.

6) Workshop according to any one of claims 3 to 5 wherein, in 5 said loading area, the punches (210) and the skirts (1) follow parallel trajectories while their axes arrive substantially in coincidence and where a means loading (280) attached to the third transfer means (10) imposes on a skirt a relative movement of axial translation in the direction of the punch so that the skirt w is fitted with little play in the punch by its first open end , said relative translation being stopped when said skirt is almost entirely fitted around the punch, one of its ends intended to be welded to the head, projecting from the head of the punch.

7) Workshop according to any one of claims 3 to 6 wherein the second zone comprises several third transfer means passing said loading area (I) where the loading means (280) act in a grouped fashion to simultaneously feed the punch (210) moved by each third transfer means (10) with a skirt (1) of the first 0 transfer means (100).

8) Workshop according to any one of claims 1 to 7, wherein the movement of the dies (240) is also continuous and follows the general movement imposed by the third transfer means (10). 5

9) Workshop according to claim 8 dependent on claims 3 to 7, wherein said dies (240) are continuously integral with the third transfer means (10), and wherein, outside the manufacturing area (II), l relative distance of the punches (210) with respect to the dies (240) is done in a direction perpendicular to the common direction of the axes of the punches and dies and the trajectory imposed by the third transfer means.

10) Workshop according to any one of claims 3 to 9 wherein one of the molding tools (the punch (210) or the die (240)) is subjected to an axial translation movement integral with the third transfer means (10) and where the other molding tool (the die (240) or the punch (210)) is supported by a support means over the entire part of the path where the other molding tool approaches and where the two remain integral .

1 1) Workshop according to any one of claims 4 to 10 wherein, in the unloading area, the punches (210) provided with the tubes (5) and the buckets (310) follow parallel paths while their axes arrive substantially coincidentally and where an unloading means attached to the third transfer means imposes on the tubes a relative movement of axial translation in the direction of the bucket.

12) Workshop according to claim 7 wherein said several third transfer means (10) pass through said unloading area (III) where the unloading means act in a group to simultaneously strip each punch (210) of each third transfer means (10) and supply the second transfer means (300) with tubes (5).

13) Workshop according to any one of claims 1 to 12 wherein the loading means (280) pushes the skirt by one of its ends towards the punch (210) and the unloading means comprises a pipe formed in the punch (210 ), opening in one or more places of the head (230) of the punch and through which a jet of compressed air is passed. 14) Workshop according to any one of claims 1 to 13 wherein the blanks are obtained by extrusion with a stationary extruder and then removed and deposited in the passage of a die or a punch.

15) Workshop according to any one of claims 1 to 13 wherein the extruded blanks are deposited in the air gap of the molding devices in a continuous movement synchronized with that of the third transfer means

16) Workshop according to claim 15 wherein the extrusion is carried out with means moved by a fourth transfer means synchronized with the third transfer means, locally imposes on said extrusion means a trajectory parallel to that of the punches or to that dies intended for collecting the blanks, the axis of extrusion coming substantially in coincidence with the axis of the receiving tool, over a length sufficient for the quantity of plastic material desired to be extruded.

17) Workshop according to claim 15 wherein the extrusion is carried out with a stationary extruder and where one or more fourth (s) transfer means (s) transfers (s) in a continuous movement of the intermediate receptacles which collect the blanks in the process .

18) Workshop according to any one of claims 14 to 17 wherein the extruded blank is toroidal and where the receiving part is provided with a perforating pin (371) whose end comes to touch the die, moving with respect to said die so that the time necessary to travel the internal diameter of the central hole of the toroidal blank corresponds to the duration of extrusion making it possible to obtain the quantity of plastic material required 19) Workshop according to claim 15 wherein a fifth transfer means transfers in a discontinuous movement the blanks thus extruded through receptacles which receive the extrudates when stopped and then are set in motion so as to be able to deposit the blanks in the air gap of the molding device driven by the third transfer means.

20) Device (10) intended to equip the workshop according to any one of claims 1 to 19 characterized in that it puts in a continuous global circular movement all of the molding devices (200), the loading means (280) skirts (1) and the means for unloading the tubes (5), each molding device comprising a mandrel (210) moved by an axial translation means acting at one of its ends (220) and a matrix (240 ) placed on a die holder (250) moved by a radial displacement means, said die holder (250) carrying a hole (260) to allow the skirt (1) to pass during its fitting around the punch (210), then as the die moves over a larger diameter to collect the blank.

21) Device (10) according to claim 20 wherein the axial translation means is a cam follower (220) attached to the end of the punch (210) held by an elastic means in constant contact with the raceway a fixed cam, while a cylindrical portion (215) of the punch (210) slides in a sleeve which follows the overall circular movement of said device.

22) Device according to claim 20 or 21 wherein the loading means is a loading fork (280) associated with a cam follower maintained by an elastic means in constant contact with the raceway of a fixed cam. 23) Device according to any one of claims 20 to 22 wherein the unloading means comprises a pipe formed in the punch and connected to a source of compressed air.

24) Workshop according to claim 17 wherein the extruded blank, of substantially toroidal shape, is obtained by shearing on passing an extrudate (805) in the form of thick tube, the shearing being carried out by a blade (821) which integral with said (or said) fourth (s) transfer means (810) and serves as a receptacle (820) for the blank thus sheared.

25) Workshop according to claim 24 wherein the blade (821) has a V shape, the angle of the V preferably being between 80 ° and 120 °.

26) Workshop according to claim 24 or 25 wherein said substantially toroidal blank is put in place, by gravity and / or with the help of an air jet, in the air gap between the molding tools.

27) Workshop according to claim 14 wherein said blanks are placed in the air gap between the molding tools and are then compressed by mutual approximation of said movable parts until relative immobilization of said movable parts, so that the heads of tube thus molded have a neck (903) whose upper end is surmounted by a cover (904) which has at least one transverse wall (905) which comprises a breakable zone (906) whose outline delimits the desired shape of the orifice and which is surrounded by two zones capable of resisting the mechanical force necessary to break said breakable zone, one (907 and 909) of them being intended to transmit said mechanical force and the other (908) to serve as a support, and in which, after opening of said molding tool by relative displacement of the punch and the matrix, the said cover is removed by applying said mechanical force on a part of the cover separated from the breakable zone by the zone (907 and 909) capable of transmitting said mechanical force, the application of said mechanical force having as consequences the rupture of the breakable zone (906) and obtaining the orifice.

28) Workshop according to claim 27 wherein said breakable zone (906) is notched with a V-notch, the angle of the V being between 30 and 90 °, preferably between 40 and 50 °, the bisector (963) of the V making an angle between 0 and 45 ° with the axis (1000) of said neck (903).

29) Workshop according to claim 27 or 28, wherein the rupture of the breakable zone (906) is carried out during cooling after molding, as soon as the plastic material reaches at the breakable zone a temperature slightly lower than its temperature glass transition.

30) Workshop according to any one of claims 27 to 29 wherein the cover (904) has a shape allowing cooperation with an element not following the continuous movement of the entire third transfer means (10), such so that the rupture is triggered by the difference in movement between this element and said third transfer means.

31) Workshop according to any one of claims 27 to 30 in which the cover (904) comprises a transverse wall (905) and a rod (909) and in which a stationary finger is placed so that its end (910 ) is located in the path of the end of the rod (909) at a distance such that the breakable zone (906) is cooled to a temperature close to the glass transition temperature when the tube head (901) reaches this position, the end of the stick being thus immobilized by the finger while the base of the stick continues its continuous movement (D) integral with the movement of the third transfer means (10).

32) Workshop according to any one of claims 27 to 30 wherein the cover is a section in the form of an inverted T, so that the removal of said cover is achieved by a simple trapping of the end of the cover in T in a rail (940) immobile and not tangent to the trajectory of the tube heads (901).

33) Method for manufacturing flexible tubes (5) comprising a skirt (1) and a head provided with a neck and a shoulder connecting said neck to said skirt, said method comprising the following steps:

- A first step in which skirts (1) are animated with a continuous movement using a first transfer means (100); - a second step in which said skirts are loaded using loading means (280) on punches (210) associated with a third transfer means (10) animated by a continuous movement synchronized with the first transfer means (100), one of the ends (3) of the skirts (1) slightly projecting from the punches (280); - A third step in which the flexible tubes are produced by molding the head with autogenous welding on one end (3) of the skirt, the head being obtained by compression molding of a blank, by relative approximation of the punch (280) provided of the skirt and of a matrix (240), said punch and said matrix defining when they are joined a mold cavity where the end of the skirt is trapped, said punch and said matrix being animated by a movement of continuous assembly corresponding to the movement of the third transfer means (10), said blank being deposited before compression in the air gap between the punch and the die using a fourth transfer means (810) αnimated by a continuous movement synchronized with the third transfer means (10);

- A fourth step in which said tubes (5) are unloaded using unloading means on a second transfer means (300) s animated by a continuous movement synchronized with the third transfer means (10).

34) A method of manufacturing assemblies of plastic parts, said method comprising the following steps: 0 - a first step in which at least one (1) of the parts of the assembly, already carried out, is set in continuous motion at using a first transfer means (100);

- A second step in which said part is loaded using loading means (280) on one of the molding tools, certain parts of said part projecting from the tooling so that, when the molding tools are attached , they define a molding cavity in which these parts are trapped, said molding tool being associated with a third transfer means (10) driven by a continuous movement synchronized with the first transfer means (100); - A third step in which the assemblies are made by molding an intermediate piece in which the projecting part of said piece is welded in an autogenous manner or trapped by the plastic of the intermediate piece, said intermediate piece being obtained by compression molding of '' a blank, by relative approximation of said molding tools, said molding tools being driven by a continuous overall movement corresponding to the movement of the third transfer means (10), said blank being deposited before compression in the air gap between the molding tools using a fourth transfer means (810) driven by a continuous movement synchronized with the third transfer means (10); - A fourth step in which said assemblies (5) are unloaded using unloading means on a second transfer means (300) driven by a continuous movement synchronized with the third transfer means (10).

35) A method of manufacturing assemblies of plastic parts according to claim 34 modified in that said molding tools are shaping tools and in that, in the third step, said shaping tools form an intermediate piece in adhesive polymeric material which adheres to parts already produced.